A. Field of the Invention
The present invention relates to a vehicle, and in particular to a vehicle which can be inclined on an inclined portion of an escalator and can ride up and down on a plurality of moving steps of the escalator.
B. Description of the Background Art
There have been proposed various kinds of powered and motorized vehicles which have upper portions for carrying drivers and can ascend and descend stairs. For example, a powered vehicle of a crawler type has been proposed. This type of vehicle has a plurality of wheels at a lower portion of a vehicle body, and endless caterpillar belts are retained around the wheels. The vehicle of the crawler type has hooks, claws or the like at the outer surfaces of the caterpillar belts for moving up and down the stairs by rotation of the caterpillar belts. Another type of vehicle has also been proposed. This vehicle is provided with vertically movable front, rear and auxiliary wheels, of which vertical positions are controlled for ascending and descending the stairs.
All the aforementioned vehicles have structures for ascending and descending the stairs but are not designed to withstand movement on an escalator. Escalators typically have steps with a limited width, and such vehicles cannot generally ride on only one step. Therefore, the aforementioned vehicles carried by the escalator must ride on a plurality of steps, so that the body of the vehicle inclines at an angle corresponding to the inclination angle of the escalator.
When the body of the vehicle of the crawler type or the like inclines, middle portions of the caterpillar belts are brought into contact with a corner of the steps of the escalator. This reduces a contact area of the caterpillar belt, and therefore the vehicle cannot be carried stably. Also, the vehicle having the vertically movable front, rear and auxiliary wheels suffers in that the front and rear wheels ride on different steps, respectively. Therefore, the vehicle may slip downward if the front and rear wheels are not braked sufficiently.